package org.bouncycastle.x509.extension;

import java.io.IOException;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;

import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1String;
import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.X509Extensions;
import org.bouncycastle.asn1.x509.X509Name;

@SuppressWarnings({ "rawtypes", "unchecked", "deprecation" })
public class X509ExtensionUtil {
    public static ASN1Object fromExtensionValue(byte[] encodedValue)
            throws IOException {
        ASN1OctetString octs = (ASN1OctetString) ASN1Object
                .fromByteArray(encodedValue);

        return ASN1Object.fromByteArray(octs.getOctets());
    }

    public static Collection getIssuerAlternativeNames(X509Certificate cert)
            throws CertificateParsingException {
        byte[] extVal = cert
                .getExtensionValue(X509Extensions.IssuerAlternativeName.getId());

        return getAlternativeNames(extVal);
    }

    public static Collection getSubjectAlternativeNames(X509Certificate cert)
            throws CertificateParsingException {
        byte[] extVal = cert
                .getExtensionValue(X509Extensions.SubjectAlternativeName
                        .getId());

        return getAlternativeNames(extVal);
    }

    private static Collection getAlternativeNames(byte[] extVal)
            throws CertificateParsingException {
        if (extVal == null) {
            return Collections.EMPTY_LIST;
        }
        try {
            Collection temp = new ArrayList();
            Enumeration it = DERSequence
                    .getInstance(fromExtensionValue(extVal)).getObjects();
            while (it.hasMoreElements()) {
                GeneralName genName = GeneralName.getInstance(it.nextElement());
                List list = new ArrayList();
                // BEGIN android-changed
                list.add(Integer.valueOf(genName.getTagNo()));
                // END android-changed
                switch (genName.getTagNo()) {
                    case GeneralName.ediPartyName:
                    case GeneralName.x400Address:
                    case GeneralName.otherName:
                        list.add(genName.getName().getDERObject());
                        break;
                    case GeneralName.directoryName:
                        list.add(X509Name.getInstance(genName.getName())
                                .toString());
                        break;
                    case GeneralName.dNSName:
                    case GeneralName.rfc822Name:
                    case GeneralName.uniformResourceIdentifier:
                        list.add(((ASN1String) genName.getName()).getString());
                        break;
                    case GeneralName.registeredID:
                        list.add(DERObjectIdentifier.getInstance(
                                genName.getName()).getId());
                        break;
                    case GeneralName.iPAddress:
                        list.add(DEROctetString.getInstance(genName.getName())
                                .getOctets());
                        break;
                    default:
                        throw new IOException("Bad tag number: "
                                + genName.getTagNo());
                }

                temp.add(list);
            }
            return Collections.unmodifiableCollection(temp);
        } catch (Exception e) {
            throw new CertificateParsingException(e.getMessage());
        }
    }
}
